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#import "TestView.h"
#import "IplImageUtil.h"
 
@implementation TestView
 
- (void)drawRect:(CGRect)rect {
  // リソース画像ロード
  NSString* path  = [[NSBundle mainBundle] pathForResource:@"lena" ofType:@"jpg"];
  UIImage*  image = [UIImage imageWithContentsOfFile:path];
  printf("@ TestView::drawRect %p @\n", image);
  [image drawAtPoint:CGPointMake(40, 20)];
 
  // ロードした画像を元にヒストグラムを作成して表示する
  IplImage* iplImage     = [IplImageUtil CreateIplImageFromUIImage:image];
  IplImage* iplHistImage = [self createHistgram:iplImage size:cvSize(240, 240)];
  UIImage*  histImage    = [IplImageUtil UIImageFromIplImage:iplHistImage];
  [histImage drawAtPoint:CGPointMake(40, 260)];
}
 
/**
 * ヒストグラム画像作成
 */
- (IplImage*)createHistgram:(IplImage*)srcImg size:(CvSize)imageSize {
    IplImage* target = srcImg;
	IplImage* gray = NULL;
 
	// ターゲットがカラーの場合はグレースケールに変換
    if (target->nChannels > 1) {
	  gray = cvCreateImage(cvSize(srcImg->width, srcImg->height), IPL_DEPTH_8U, 1);
	  cvCvtColor(srcImg, gray, CV_BGR2GRAY);
	  target = gray;	  
	}
 
	// ヒストグラム作成
    int    channelSize[] = { 256 };
	float  levelRange[]  = { 0, 256 };
	float* range[]       = { levelRange };
	CvHistogram* hist    = cvCreateHist(1, channelSize, CV_HIST_ARRAY, range, 1);
	cvCalcHist(&target, hist, 0, NULL);
 
	// ヒストグラム出力用画像作成
	IplImage* dstImg = cvCreateImage(imageSize, IPL_DEPTH_8U, 3);
	cvSet(dstImg, cvScalarAll(255), 0);
 
	// ヒストグラムのスケール変換
	float max = 0;
	cvGetMinMaxHistValue(hist, 0, &max, 0, 0);
	cvScale(hist->bins, hist->bins, ((double)dstImg->height) / max, 0);
 
	// 画像に出力
	int binWidth = cvRound((double)imageSize.width / channelSize[0]);
	for (int i = 0; i < channelSize[0]; i++) {
	    int     histValue  = cvRound(cvQueryHistValue_1D(hist, i));
	    CvPoint bottomLeft = cvPoint(i * binWidth, dstImg->height);
	    CvPoint topRight   = cvPoint((i+1) * binWidth, dstImg->height - histValue);
	    cvRectangle(dstImg, bottomLeft, topRight, cvScalarAll(0), CV_FILLED, 8, 0);
	}
 
	// ヒストグラム破棄
	cvReleaseHist(&hist);
	if (gray) cvReleaseImage(&gray);
 
	return dstImg;
}
 
@end